Technology related to semiconductor integrated circuitry has been vigorously advancing in recent years, and even those constitutions that were not technically feasible are now drawing consideration. For example, modern applications for multi-media technology are demanding high-speed processing of great amounts of data even in cell-powered portable data terminal equipment (or a portable data terminal-system), as well as a decrease in the size and a weight and decrease in the amount of power consumption thereof. In order to meet these demands, it can be considered to mount the data processing circuits, such as a logic operation circuit and a central processing circuit, as well as a memory circuit of a relatively large capacity coupled to such a data processing device, on a single semiconductor substrate (chip) instead of constituting them as independent semiconductor integrated circuit devices. When the electronic system that is to be obtained further requires other functional circuits, such as an analog-digital converter circuit and a digital-analog converter circuit, such functional circuits, too, may be mounted on one semiconductor substrate.
In this case, it is convenient to treat the data processing circuit, memory circuit, analog-digital converter circuit, digital-analog converter circuit and the like circuits as individual modules or functional unit circuits from the standpoint of designing and producing a semiconductor integrated circuit-device. Therefore, the above-mentioned method can be regarded to be a method of mounting a plurality of different modules or functional units on a single semiconductor substrate.
The semiconductor integrated circuit device which has a constitution in which a plurality of modules having different functions are mounted on a semiconductor substrate may be considered to constitute almost all circuit portions of a desired electronic system and may, hence, be referred to as a system LSI. After the completion of the present invention, the present inventors have learned, through a search, of the presence of JP-A-8-204140, which is related to the substrate bias voltage control technology of the present invention that will be described later. According to the subject matter disclosed in this publication, the substrate bias voltages corresponding to the circuit blocks are controlled depending on the normal operation and the standby operation in the CMOS constitution that uses a silicon-on-insulator substrate. This publication, however, has no description concerning technology that can be favorably adapted to a plurality of modules or the mode-setting technology contemplated by the present invention as will be described later.